Observations of Twinning and Detwinning in Magnesium Alloy by Synchrotron Radiation DCT and EBSD

Nakai, Yoshikazu; Shiozawa, Daiki; Kikuchi, Shinichi; Nakagawa, Yuki; Asayama, Kaito

doi:10.1016/j.prostr.2020.01.067

Cited by 9 publications

(2 citation statements)

References 7 publications

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“…Similarly, bright spots would arise from grains that were in extinction in the reference image and are no longer in this condition. This points to local changes in scattering due to grain reorientation or plastic deformation [17,[47][48][49].…”

Section: Observationsmentioning

confidence: 98%

In Situ Mechanical Loading and Neutron Bragg-edge Imaging, Applied to Polygranular Graphite On IMAT@ISIS

et al. 2021

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Background Bragg edge imaging have seen significant developments in the last decade with the availability of new time-resolved detectors, however, there have been no studies of changes in local coherent scattering from grain reorientation and deformation with load. Such damage accommodation mechanism may occur in (quasi)-brittle materials. Objective We developed a novel method using in-situ Bragg imaging at the ISIS spallation neutron and muon source on the IMAT (Imaging and MATerials science and engineering) instrument using an energy-resolved detector setup. We collected and analysed data of a proof-of-concept experiment demonstrating the use of the method. Methods We have developed a loading apparatus that addresses the constraints posed by Bragg imaging, allowing us to resolve features in the material microstructure. We use energy-resolved neutron imaging to obtain images in energy bins and we have developed a set of codes to register and correlate these images, as well as detect changes in local coherent scattering, in situ. Results Preliminary results from this method on Gilsocarbon nuclear graphite allow qualitative observation of local changes in Bragg contrast, which may be due to deformation or grain reorientation. Conclusions We have demonstrated that we can track changes in local coherent scattering under mechanical load, with sufficient resolution to track features with a size above 100 microns. This method, apparatus and accompanying codes may be used on the IMAT instruments by users interested to better understand deformation in their materials.

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Section: Observationsmentioning

confidence: 98%

In Situ Mechanical Loading and Neutron Bragg-edge Imaging, Applied to Polygranular Graphite On IMAT@ISIS

et al. 2021

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“…Then, twinning is essential to understand cold working process, where all grains should be received plastic deformation. On the other hand, detwinning was observed under tension stress after twinning under compression stress [1][2][3][4][5]. This phenomenon may concern with fatigue process; however, it has not been clear whether the twinning-detwinning phenomena occurred in each cyclic loading, and whether the fatigue crack initiation was affected by them or not.…”

Section: Introductionmentioning

confidence: 99%

Stress Ratio Effect on Fatigue Crack Initiation Mechanism of Magnesium Alloy AZ31

Nakai

Kikuchi

Asayama

et al. 2021

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Fatigue tests were conducted under several stress ratios, including negative maximum stress to elucidate the fatigue crack initiation mechanism of a magnesium alloy, AZ31. The specimen surface near the crack initiation site was analyzed by EBSD. On the basis of the results of EBSD analysis, it is concluded for an alternating cyclic stress condition (fully reversed cyclic stress) that fatigue cracks formed from grains where both the grain size and Schmid factor of the basal slip system are large, and that the crack initiation mechanism is based on irreversible slipping and unrelated to twinning. Under compression-compression fatigue test (R=10), cracks were formed along boundary of grains with large Schmid factor and misfit of both side grain are large. At the tip of the initiated crack, twin bands were observed.

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Effect of multifunction cavitation using phosphoric acid on fatigue and surface properties of AZ31 magnesium alloy

Matsuoka

Kato

Yoshimura

et al. 2023

Journal of Magnesium and Alloys

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Observations of Twinning and Detwinning in Magnesium Alloy by Synchrotron Radiation DCT and EBSD

Cited by 9 publications

References 7 publications

In Situ Mechanical Loading and Neutron Bragg-edge Imaging, Applied to Polygranular Graphite On IMAT@ISIS

In Situ Mechanical Loading and Neutron Bragg-edge Imaging, Applied to Polygranular Graphite On IMAT@ISIS

Stress Ratio Effect on Fatigue Crack Initiation Mechanism of Magnesium Alloy AZ31

Effect of multifunction cavitation using phosphoric acid on fatigue and surface properties of AZ31 magnesium alloy

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